In a quart pot, stir together a half cup granulated sugar, 2 tablespoons cornstarch, and 3 ounces of good cocoa. To this add well whipped 3 egg yolks and a cup each whole milk and cream.
Blend very well and bring to heat slowly, whisking continually until mixture begins to thicken. Take care not so scorch. When thick, blend in two pats of butter and a teaspoon of pure vanilla extract.
While still warm, pour the pudding through a strainer into a bowl. Refrigerate until cold. Use a fine whisk to cream pudding before spooning into serving containers.
